Ion beam etching chamber with etching by-product redistributor

ABSTRACT

In some embodiments, the present disclosure relates to an etching apparatus. The etching apparatus includes a substrate holder disposed within a processing chamber and having a workpiece reception surface configured to hold a workpiece. A lower surface of the processing chamber has a first region that is directly below the workpiece reception surface and that is configured to receive a byproduct from an etching process. A baffle extends outward from a sidewall of the processing chamber at a vertical position between the substrate holder and the lower surface of the processing chamber. The baffle covers a second region of the lower surface. A byproduct redistributor is configured to move the byproduct from the first region of the lower surface to the second region of the lower surface that is directly below the baffle.

REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. application Ser. No.15/991,029, filed on May 29, 2018, the contents of which are herebyincorporated by reference in their entirety.

BACKGROUND

Ion beam etching (i.e., ion beam milling) is a commonly used etchingprocess used during the fabrication of integrated chips. Ion beametching is an anisotropic etching process that is able to preferentiallyremove a material in a specific direction. By removing a material in aspecific direction, high density features can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a block diagram of some embodiments of a disclosedion beam etching apparatus having one or more baffles configured toreduce re-deposition of an etching by-product onto a workpiece.

FIG. 2 illustrates a block diagram of some additional embodiments of adisclosed ion beam etching apparatus having one or more baffles.

FIG. 3 illustrates some embodiments of a timing diagram showingoperation of the ion beam etching apparatus of FIG. 2.

FIG. 4 illustrates a block diagram of some additional embodiments of adisclosed ion beam etching apparatus having one or more baffles.

FIGS. 5A-5B illustrates top-views of some embodiments of a disclosed ionbeam etching apparatus having one or more baffles.

FIGS. 6A-6D illustrates cross-sectional views of some embodiments of oneor more baffles as provided herein.

FIGS. 7-10 illustrate cross-sectional views of some embodiments of amethod of performing an ion beam etching process.

FIG. 11 illustrates a flow diagram of some embodiments of a method d ofperforming an ion beam etching process.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Ion beam etching is a dry etching process that etches a material on aworkpiece by bombarding the material with an ion beam comprising chargedions. To perform ion beam etching, a workpiece is loaded into aprocessing chamber and the processing chamber is pumped down to a highvacuum (i.e. a low pressure). A plasma is formed within a plasma sourcein communication with the processing chamber and an ion beam is thengenerated by acting on the plasma with an electric field thataccelerates ions from the plasma towards the workpiece. When the chargedions strike the material with a sufficient energy they will dislodgeparticles of the material, thereby etching the material.

Particles that are dislodged from the workpiece by an ion beam etchingprocess generally adhere to interior surfaces (e.g., sidewalls, a floor,and/or ceiling) of a processing chamber. However, some materials, suchas ceramics (e.g., piezoelectric materials) do not adhere well to theinterior surfaces of the processing chamber. It has been appreciatedthat when a processing chamber is vented (i.e., returned from lowpressure to an ambient pressure after an etching process is completed),gases within the processing chamber can become turbulent and cause suchparticles to become airborne. The airborne particles can be re-depositedonto the workpiece causing reliability problems and reducing yield of anintegrated chip on the workpiece. For example, the re-deposition of aconductive by-product onto an integrated chip workpiece may lead toelectrical shorting and integrated chip failure.

The present disclosure, in some embodiments, relates to an ion beametching apparatus that is configured to reduce re-deposition of anetching by-product onto a workpiece. The ion beam etching apparatuscomprises a substrate holder disposed within a processing chamber andconfigured to hold a workpiece. The processing chamber is incommunication with a plasma source configured to provide ions that areaccelerated towards the substrate holder as an ion beam, and with avacuum pump configured to reduce a pressure within the processingchamber. One or more baffles are arranged between the substrate holderand a lower surface of the processing chamber. A by-productredistributor is configured to move a by-product from an etching processfrom outside of the one or more baffles to directly below the one ormore baffles. By moving the by-product from the etching process todirectly below the one or more baffles, the one or more baffles are ableto mitigate re-deposition of the by-product from the etching processback onto the workpiece, thereby decreasing defects on the workpiece andincreasing yield.

FIG. 1 illustrates a block diagram of some embodiments of a disclosedion beam etching apparatus 100 having one or more baffles configured toreduce re-deposition of an etching by-product onto a workpiece.

The ion beam etching apparatus 100 comprises a substrate holder 104arranged within a processing chamber 102. The processing chamber 102 hasa housing comprising a sidewall 102 s arranged between an upper surface102 u and a lower surface 102 l. The substrate holder 104 is configuredto hold a workpiece 106 (e.g., comprising a semiconductor substrate)that is to be etched. The processing chamber 102 is in communicationwith a plasma source 108 that is configured to generate a plasma 110. Invarious embodiments, the plasma source 108 may comprise an inductivelycoupled plasma (ICP) source, a direct current plasma (DCP) source, amicrowave-induced plasma (MIP) source, or the like.

A grid system 112 is arranged between the plasma source 108 and thesubstrate holder 104. The grid system 112 is configured to form an ionbeam 114 by generating an electromagnetic field within the processingchamber 102. The electromagnetic field accelerates ions from the plasma110 into the processing chamber 102 in a direction of the substrateholder 104. The ion beam 114 is configured to bombard a surface of theworkpiece 106. Ions that impact the surface of the workpiece 106 with asufficient energy will perform an etching process by dislodgingparticles from the workpiece 106. The dislodged particles fall towardsthe lower surface 102 l of the processing chamber 102 as a by-product ofthe etching process.

The processing chamber 102 is coupled to a vacuum pump 116 by way of avacuum inlet 118. In some embodiments, the vacuum inlet 118 may bewithin the upper surface 102 u of the processing chamber 102. In otherembodiments, the vacuum inlet 118 may be within other surfaces (e.g.,the sidewall 102 s) of the processing chamber 102. The vacuum pump 116is configured to reduce a pressure within the processing chamber 102during operation. Reducing a pressure within the processing chamber 102allows for formation of the ion beam 114 and reduces contamination ofthe workpiece 106 during the etching process. In various embodiments,the vacuum pump 116 may comprise a roughing pump and/or a high vacuumpump. In some embodiments, a first valve 119 may be configured toselectively allow the vacuum pump 116 to pump down the processingchamber 102.

One or more baffles 120 are arranged along a perimeter of the processingchamber 102. The one or more baffles 120 are arranged at a verticalposition that is below the substrate holder 104. In some embodiments,the one or more baffles 120 are arranged at a vertical position that isbetween the substrate holder 104 and a lower surface 102 l of theprocessing chamber 102. In some embodiments, the one or more baffles 120laterally extend over a part of the lower surface 102 l of theprocessing chamber 102 and are separated from the lower surface 102 l ofthe processing chamber 102 by a non-zero distance. In some embodiments,the one or more baffles 120 comprise sidewalls that are separated by aspace that is directly below the substrate holder 104. In someembodiments, the one or more baffles 120 may be coupled to the sidewall102 s of the processing chamber 102. In other embodiments (not shown),the one or more baffles 120 may be coupled to the lower surface 102 l ofthe processing chamber 102.

A by-product redistributor 122 is configured to redistribute (shown byarrows 124) the by-product 115 of the etching process from outside of(i.e., not directly below) the one or more baffles 120 to directly belowthe one or more baffles 120. By operating the by-product redistributor122 to redistribute the by-product 115 of the etching process fromoutside of the one or more baffles 120 to directly below the one or morebaffles 120, the one or more baffles 120 are able to prevent theby-product 115 of the etching process from being re-deposited on theworkpiece 106 when the chamber is vented (i.e., returned from lowpressure to an ambient pressure after the etching process is completed),thereby improving reducing defects on the workpiece 106 and increasingyield.

FIG. 2 illustrates a block diagram of some additional embodiments of adisclosed ion beam etching apparatus 200 having one or more baffles.

The ion beam etching apparatus 200 includes a processing chamber 102comprising a housing having sidewalls coupled between an upper surfaceand a lower surface 102 l. In some embodiments, the housing may comprisea metal, such as aluminum, iron, or the like. A rotatable stage assembly202 is disposed within the processing chamber 102. The rotatable stageassembly 202 comprises a workpiece reception area having a flat surfaceconfigured to receive a workpiece 106. The workpiece reception area iscoupled to a mounting arm 203 by a joint 204 that is configured torotate about one or more axes of rotation, so as to control an angle atwhich an ion beam 114 is able to strike the workpiece 106. In someembodiments, the rotatable stage assembly 202 may be configured torotate so as to enable the ion beam 114 to strike the workpiece 106 atan angle of between +/−90 degrees. In some embodiments, the rotatablestage assembly 202 may be coupled to a chamber door 206 that is attachedto the processing chamber 102 by one or more hinges configured to enablethe chamber door 206 to swing open during loading of workpieces into theprocessing chamber 102

A plasma source 108 is coupled to the processing chamber 102. In someembodiments, the plasma source 108 comprises a plasma chamber 208 havinga housing. The plasma chamber 208 is coupled to a gas source 210 (e.g.,gas tank) by way of a gas inlet 209 arranged within an interior surfaceof the plasma chamber 208. In some embodiments, a second valve 211 maybe configured to selectively allow the gas source 210 to introduce a gasinto the plasma chamber 208. An RF antenna 212 is in communication withthe plasma chamber 208. The RF antenna 212 is coupled to an RF powersupply 214 configured to generate an RF signal. In some embodiments, theRF power supply 214 may operate at a set RF frequency (e.g., 13.56 MHz).In some embodiments, the RF power supply 214 may be coupled to the RFantenna 212 by way of a matching network 216 that is configured to matchthe output impedance of the RF power supply 214 to a complex impedanceestablished by the RF antenna 212 and a plasma load (i.e., impedance),thereby efficiently coupling power from the RF power supply 214 into aplasma 110 within the plasma chamber 208.

In some embodiments, the RF antenna 212 may comprise a conductive coilcomprising a conductive wire. In one embodiment, the conductive coil maybe wrapped around an exterior of the plasma chamber 208 for a pluralityof turns. In alternative embodiments, the conductive coil may becomprised within an interior of the plasma chamber 208. The inductivecoil is configured to generate an electromagnetic field that transfersenergy from the RF power supply 214 to gas particles within the plasmachamber 208 to form an inductively coupled plasma. For example, the RFpower supply 214 may generate a time-dependent current that produces atime varying magnetic field within the plasma chamber 208, which inducesa time-varying electric field that accelerates charged particles to anenergy that is sufficient to ionize the gas within the plasma chamber208 by way of ionizing collisions.

A grid system 112 is arranged between the plasma source 108 and therotatable stage assembly 202. The grid system 112 is configured toaccelerate ions from the plasma 110 towards the rotatable stage assembly202 as an ion beam 114. In some embodiments, the grid system 112 maycomprise a multiple grids. For example, the grid system 112 may comprisea first grid, a second grid, and a third grid. The first grid is incontact with the plasma 110, and may be biased to a positive voltage todefine a beam voltage or energy. The second grid may be biased to anegative voltage to accelerate ions from the plasma 110 into the ionbeam 114. The third grid is normally grounded and helps reducedivergence of the ion beam 114. In some embodiments, the grid system 112may comprise one or more grids respectively comprising a sheet ofconductive material (e.g., a metal) having a plurality of aperturesextending therethrough. In other embodiments, the grid system 112 maycomprise one or more grids respectively comprising a plurality ofconductive wires or strips extending between various points on an outerconductive ring to define a plurality of apertures.

One or more baffles 120 are arranged along a perimeter of the processingchamber 102. In various embodiments, the one or more baffles 120 maycomprise a conductive material, such as a metal (e.g., aluminum, tin,copper, or the like). In other embodiments, the one or more baffles 120may comprise an insulating material (e.g., a plastic, a ceramic, or thelike). The one or more baffles 120 are arranged at a vertical positionthat is between the rotatable stage assembly 202 and the lower surface102 l of the processing chamber 102. The one or more baffles 120laterally extend over a part of the lower surface 102 l of theprocessing chamber 102 and are separated from the lower surface 102 l ofthe processing chamber 102 by a non-zero distance. In some embodiments,the one or more baffles 120 may be coupled to sidewalls of theprocessing chamber 102.

In some embodiments, the one or more baffles 120 may comprise a firstlower surface 120 a and a second lower surface 120 b that is between thefirst lower surface 120 a and the lower surface 102 l of the processingchamber 102. The second lower surface 120 b is arranged along anoutermost edge of the one or more baffles 120. By vertically extendingto the second lower surface 120 b, the one or more baffles 120 are ableto better contain a by-product of an etching process that has been moveddirectly below the one or more baffles 120 by a by-product redistributor122.

In some embodiments, the by-product redistributor 122 comprises one ormore coolers 218 a-218 b. The one or more coolers 218 a-218 b arearranged directly below the one or more baffles 120 and are configuredto decrease a temperature below the one or more baffles 120. Bydecreasing a temperature below the one or more baffles 120, atemperature gradient is formed within the processing chamber 102. Thetemperature gradient along the bottom of the chamber that decreases in adirection from directly below the one or more baffles to the outside of(i.e., not directly below) the one or more baffles 120. The temperaturegradient is configured to move the by-product of the etching process tobelow the one or more baffles 120 by enhancing diffusion of theby-product of the etching process to below the one or more baffles 120(e.g., according to a thermophoretic force generated bythermodiffusion). In some embodiments, the temperature gradient may begreater than or equal to approximately 10° C. Such a temperaturegradient is sufficient to induce a thermophoretic force to move theby-product of the etching process. In some additional embodiments, thetemperature gradient may be in a range of between approximately 10° C.and approximately 50° C.

In some embodiments, the by-product redistributor 122 may furthercomprise a heater 220 arranged outside of (i.e., not directly below) theone or more baffles 120. For example, the heater 220 may be arrangedlaterally between the one or more baffles 120 (e.g., in a center of theprocessing chamber 102). The heater 220 is configured to heat anoverlying area of the processing chamber 102, so as to increase thetemperature gradient in a direction from directly below the one or morebaffles to the outside of the one or more baffles 120 and improvemovement of the by-product of the etching process.

In various embodiments, the one or more coolers 218 a-218 b may comprisepipes configured to transport a cool liquid, a coil (e.g., that movesheat by way of a vapor compression), a thermoelectric heat pump, or thelike. In various embodiments, the heater 220 may comprise pipesconfigured to transport a hot liquid, a coil (e.g., that removes heat byway of a vapor compression), a thermoelectric heat pump, a resistiveheater, or the like. In some embodiments, the one or more coolers 218a-218 b and/or the heater 220 may be arranged below the lower surface102 l of the processing chamber 102. In other embodiments, the one ormore coolers 218 a-218 b and/or the heater 220 may be arranged withinthe processing chamber 102. For example, in some embodiments, the one ormore coolers 218 a-218 b and/or the heater 220 may comprise pipesextending into the processing chamber 102, which are configured to carrya heating and/or cooling liquid.

In some embodiments, a control unit 222 may be configured to selectivelycontrol operation of one or more of the vacuum pump 116, the first valve119, the second valve 211, the RF power supply 214, the grid system 112,the one or more coolers 218 a-218 b, and/or the heater 220. FIG. 3illustrates a timing diagram 300 showing some embodiments of operationof the control unit 222 on the disclosed ion beam etching apparatus 200of FIG. 2. It will be appreciated that the operation illustrated intiming diagram 300 is one non-limiting example of operation of thedisclosed ion beam etching apparatus 200 and that in other embodimentsthe operation may be different. Furthermore, the reference numeralsincluded in the description of timing diagram 300 set forth belowcorrespond to FIG. 2 unless otherwise noted.

As shown in timing diagram 300, at a first time T₁ the first valve 119is opened and the vacuum pump 116 is turned on to reduce a pressurewithin the processing chamber 102. In various embodiments, the vacuumpump 116 may be kept on continuously, kept on intermittently (i.e.,turned on and off), or kept off between the first time T₁ and asubsequent fifth time T₅. At a second time T₂, the second valve 211 isopened to introduce a gas into the plasma chamber 208. At a third timeT₃, the RF power supply 214 is turned on. Turning on the RF power supply214 causes a plasma 110 to form within the plasma chamber 208. At afourth time T₄ a bias voltage is applied to the grid system 112 so as toaccelerate ions from the plasma 110 towards the rotatable stage assembly202. At a fourth time T₄, the by-product redistributor 122 is alsooperated to move a by-product (e.g., 115 of FIG. 1) of the etchingprocess to below the one or more baffles 120. At a fifth time T₅, theetching process is completed. Upon completion of the etching process,the second valve 211 is closed, the RF power supply 214 is turned off,the grid system 112 is turned off, and the by-product redistributor 122is turned off. At a sixth time T₆, the vacuum pump 116 is turned off andthe processing chamber 102 is vented. Venting the processing chamber 102increases a pressure within the processing chamber 102 back to anambient pressure (i.e., a pressure outside of the processing chamber102).

FIG. 4 illustrates a block diagram of some additional embodiments of adisclosed ion beam etching apparatus 400 having one or more baffles.

The ion beam etching apparatus 400 comprises a by-product redistributor122 having one or more additional vacuum pumps 402 a-402 b coupled to aprocessing chamber 102 by way of one or more additional inlets 404 thatare arranged directly below one or more baffles 120. The one or moreadditional vacuum pumps 402 a-402 b are configured to generate apressure gradient along the bottom of the chamber that decreases in adirection from below the one or more baffles to the outside of the oneor more baffles 120. The pressure gradient is configured to move theby-product of an etching process from outside of the one or more baffles120 to below the one or more baffles 120 by acting upon the particleswith a force. In some embodiments, the pressure gradient may be greaterthan or equal to approximately 10¹ Torr. For example, in someembodiments, the pressure outside of the one or more baffles 120 may be10⁻⁵ Torr while the pressure below the one or more baffles 120 may be10⁻⁶ Torr. In other embodiments, the pressure gradient may be less than10¹ Torr.

In some embodiments, the one or more baffles 120 may comprise a mobileflap (not shown) that is configured to operate as a valve that keeps theby-product of the etching process directly below the one or more baffles120. For example, the one or more baffles 120 may comprise a hinge thatis coupled to a mobile flap extending below the one or more baffles 120.The lower pressure generated by the one or more additional vacuum pumps402 a-402 b will open the mobile flap so as to allow the by-product ofthe etching process to move below the one or more baffles 120. If thepressure below the mobile flap is increased, it will cause the valve toclose thereby trapping the by-product of the etching process below theone or more baffles 120.

FIGS. 5A-5B illustrates top-views, 500 and 508, of some embodiments of adisclosed ion beam etching apparatus having one or more baffles.

As shown in top-view 500 of FIG. 5A, a single baffle 502 is arrangedalong an outer perimeter of a processing chamber 102. The single baffle502 continuously extends around the outer perimeter in an unbroken ringshape over a by-product redistributor 504. In some embodiments, thesingle baffle 502 may comprise a second lower surface 506 that extendsalong an edge of the single baffle 502 as an unbroken ring.

In some embodiments, the by-product redistributor 504 may comprise acooler that continuously extends below the single baffle 502 as anunbroken ring. In other embodiments (not shown), the by-productredistributor may comprise a plurality of coolers may be positioned atseparate and discrete locations below the single baffle 502. In somealternative embodiments, the by-product redistributor 504 may comprisean inlet coupled to a vacuum pump, which continuously extends below thesingle baffle 502 as an unbroken ring. In yet other embodiments (notshown), the by-product redistributor may comprise a plurality of coolinginlets positioned at separate and discrete locations below the singlebaffle 502 and coupled to one or more vacuum pumps.

As shown in top-view 508 of FIG. 5B, a plurality of baffles 510 arearranged at discrete locations along an outer perimeter of a processingchamber 102. The plurality of baffles 510 are separated from one anotherby non-zero spaces. In some embodiments, the plurality of baffles 510respectively comprise a second lower surface 512 that continuouslyextends between different locations on a sidewall 102 s of theprocessing chamber 102.

In some embodiments, a by-product redistributor 514 may comprise aplurality of coolers respectively disposed below one of the plurality ofbaffles 510. In some alternative embodiments, the by-productredistributor 514 may comprise a plurality of inlets respectivelyarranged below one of the plurality of baffles 510 and coupled to avacuum pump.

In various embodiments, the disclosed baffles may have different shapes.FIGS. 6A-6D illustrates cross-sectional views of some embodiments ofbaffles disclosed herein. It will be appreciated that the shapes of thebaffles illustrated in FIGS. 6A-6D are non-limiting examples of theshapes of the baffles and that the disclosed baffles may have othershapes in some additional embodiments.

FIG. 6A illustrates a cross-sectional view 600 of some embodiments of adisclosed baffle 602. The disclosed baffle 602 comprises an “L” shapedstructure that has an upper surface 602 a that is parallel to a lowersurface 102 l of a processing chamber 102. The upper surface 602 a iscoupled to a first vertical sidewall 602 b and a second verticalsidewall 602 c that are perpendicular to the lower surface 102 l of theprocessing chamber 102. The first vertical sidewall 602 b contacts asidewall 102 s of the processing chamber 102 and is coupled to a firstlower surface 602 d. The second vertical sidewall 602 c is coupled to asecond lower surface 602 e that is between the first lower surface 602 dand the lower surface 102 l of the processing chamber 102.

FIG. 6B illustrates a cross-sectional view 604 of some alternativeembodiments of a disclosed baffle 606. The disclosed baffle 606comprises an upper surface 606 a that is parallel to a lower surface 102l of a processing chamber 102. The upper surface 606 a is coupled to afirst vertical sidewall 606 b that contacts a sidewall 102 s of theprocessing chamber 102. The first vertical sidewall 606 b is furthercoupled to a first lower surface 606 c that is further coupled to afirst angled surface 606 d. The upper surface 606 a is further coupledto a second angled surface 606 e that is coupled to a second lowersurface 606 f that is between the first angled surface 606 d and thesecond angled surface 606 e.

FIG. 6C illustrates a cross-sectional view 608 of some alternativeembodiments of a disclosed baffle 610. The disclosed baffle 610comprises an upper surface 610 a that is coupled to a first verticalsidewall 610 b that contacts a sidewall 102 s of a processing chamber102. The first vertical sidewall 610 b is further coupled to a firstlower surface 610 d. The upper surface 606 a is coupled to a secondlower surface 610 f by way of a first curved surface 610 c. The firstlower surface 610 d is coupled to the second lower surface 610 f by wayof a second curved surface 610 e. The second lower surface 610 f isbetween the first lower surface 610 d and the lower surface 102 l of theprocessing chamber 102.

FIG. 6D illustrates a cross-sectional view 612 of some embodiments of adisclosed baffle 614. The disclosed baffle 614 comprises an uppersurface 614 a that is parallel to a lower surface 102 l of a processingchamber 102. The upper surface 614 a is coupled to a first verticalsidewall 614 b and a second vertical sidewall 614 c that areperpendicular to the lower surface 102 l of the processing chamber 102.The first vertical sidewall 614 b is separated from a sidewall 102 s ofthe processing chamber 102 and is coupled to a first lower surface 614d. The second vertical sidewall 614 c is separated from a sidewall 102 sof the processing chamber 102 and is coupled to a second lower surface614 e. A third lower surface 614 f is arranged laterally between thefirst lower surface 614 d and the second lower surface 614 e. The thirdlower surface 614 f is coupled to a support structure 616 that connectsthe third lower surface 614 f to the lower surface 102 l of theprocessing chamber 102.

FIGS. 7-10 illustrate cross-sectional views 700-1000 of some embodimentsof a method of performing an ion beam etching process. Although thecross-sectional views 700-1000 shown in FIGS. 7-10 are described withreference to a method, it will be appreciated that the structures shownin FIGS. 7-10 are not limited to the method but rather may stand aloneseparate of the method.

As shown in cross-sectional view 700 of FIG. 7, a workpiece 106 isloaded onto a substrate holder 104 within a processing chamber 102. Insome embodiments, the workpiece 106 may comprise a semiconductorsubstrate. In various embodiments, the semiconductor substrate maycomprise any type of semiconductor body (e.g., silicon/CMOS bulk, SiGe,SOI, etc.) such as a semiconductor wafer or one or more die on a wafer,as well as any other type of semiconductor and/or epitaxial layersformed thereon and/or otherwise associated therewith. In someembodiments, the workpiece 106 may comprise an exposed ceramic material(e.g., a piezoelectric material) that is to be etched.

As shown in cross-sectional view 800 of FIG. 8, the processing chamber102 is pumped down to maintain a relatively low pressure within theprocessing chamber 102. For example, the processing chamber 102 may bepumped down to a pressure that is in a range of between approximately10⁻⁵ Torr and approximately 10⁻⁶ Torr. In some embodiments, theprocessing chamber 102 may be pumped down by operating a vacuum pump 116to decrease a pressure of the processing chamber 102.

After the processing chamber 102 is pumped down, a plasma 110 isgenerated within a plasma chamber 208 that is coupled to the processingchamber 102. In some embodiments, the plasma 110 may be generated byintroducing a gas (e.g., Argon) from a gas source 210 into the plasmachamber 208. An RF power supply 214 is subsequently operated to apply anRF signal to an RF antenna 212 in communication with the plasma chamber208. The RF signal is configured to generate an electromagnetic fieldthat transfers energy to particles of the gas within the plasma chamber208 to form an inductively coupled plasma (ICP). In some embodiments,the introducing the gas from the gas source 210 into the plasma chamber208 may increase a pressure of the processing chamber 102 to a pressureof approximately 10⁻⁴ Torr while the gas is flowing.

As shown in cross-sectional view 900 of FIG. 9, ions from the plasma 110are accelerated towards the workpiece 106 within the plasma chamber 208as an ion beam 114 that is configured to perform an etching process onthe workpiece 106. In some embodiments, the ions from the plasma areaccelerated by applying one or more bias voltages to a grid system 112disposed between the plasma 110 and the workpiece 106. The one or morebias voltages generate an electromagnetic field that acts to accelerateions within the plasma 110. The accelerated ions pass through apertureswithin the grid system 112 to form the ion beam 114.

The ion beam 114 strikes the workpiece 106. Ions with sufficient energydislodge atoms from the workpiece 106, so as to etch the workpiece 106.A by-product of the etching process 115 falls to a lower surface 102 lof the processing chamber 102 between one or more baffles 120.

As shown in cross-sectional view 1000 of FIG. 10, the by-product fromthe etching process 115 is moved from outside of (i.e., not directlybelow) the one or more baffles 120 to directly below one or more baffles120. In various embodiments, the by-product from the etching process 115may be moved to directly below the one or more baffles 120 concurrent tothe etching process and/or after the etching process is completed.

In some embodiments, the by-product 115 of the etching process may bemoved by generating a temperature gradient along the bottom of thechamber that decreases in a direction from directly below the one ormore baffles to the outside of (i.e., not directly below) the one ormore baffles 120. The temperature gradient is configured to move theby-product of the etching process to below the one or more baffles 120by enhancing diffusion of the by-product of the etching process to belowthe one or more baffles. In other embodiments, the by-product 115 of theetching process may be moved by generating a pressure gradient along thebottom of the chamber that decreases in a direction from below the oneor more baffles to the outside of (i.e., not directly below) the one ormore baffles 120.

FIG. 11 illustrates a flow diagram of some embodiments of a method 1100of forming an integrated chip having an embedded flash memory devicewith an enhanced floating gate.

While method 1100 is illustrated and described below as a series of actsor events, it will be appreciated that the illustrated ordering of suchacts or events are not to be interpreted in a limiting sense. Forexample, some acts may occur in different orders and/or concurrentlywith other acts or events apart from those illustrated and/or describedherein. In addition, not all illustrated acts may be required toimplement one or more aspects or embodiments of the description herein.Further, one or more of the acts depicted herein may be carried out inone or more separate acts and/or phases.

At 1102, a workpiece is loaded into a processing chamber. FIG. 7illustrates a cross-sectional view 700 of some embodiments correspondingto act 1102.

At 1104, the processing chamber is pumped down to reduce a pressurewithin the processing chamber from an ambient pressure to a low pressure(i.e., a high vacuum). FIG. 8 illustrates a cross-sectional view 800 ofsome embodiments corresponding to act 1104.

At 1106, a gas is introduced into a plasma chamber that is incommunication with the processing chamber. FIG. 8 illustrates across-sectional view 800 of some embodiments corresponding to act 1106.

At 1108, a plasma is generated within the plasma chamber from the gas.FIG. 8 illustrates a cross-sectional view 800 of some embodimentscorresponding to act 1108.

At 1110, ions from the plasma are accelerated towards a workpiece withinthe plasma chamber so as to etch the workpiece within the plasmachamber. FIG. 9 illustrates a cross-sectional view 900 of someembodiments corresponding to act 1110.

At 1112, a by-product from the etching process is moved directly belowone or more baffles within the processing chamber. FIG. 10 illustrates across-sectional view 900 of some embodiments corresponding to act 1112.

In some embodiments, the by-product from the etching process may bemoved directly below the one or more baffles by generating a temperaturegradient within the processing chamber, at 1114. The temperaturegradient along the bottom of the chamber that decreases in a directionfrom directly below the one or more baffles to the outside of the one ormore baffles 120.

In other embodiments, the by-product from the etching process may bemoved directly below the one or more baffles by generating a pressuregradient within the processing chamber, at 1116. The pressure gradientalong the bottom of the chamber that decreases in a direction fromdirectly below the one or more baffles to the outside of (i.e., notdirectly below) the one or more baffles 120.

At 1118, the processing chamber is vented to increase a pressure of theprocessing chamber from the low pressure (i.e., the high vacuum) to anambient pressure. Venting the processing chamber causes gases within theprocessing chamber to become turbulent. However, because the by-productfrom the etching process has been moved directly below the one or morebaffles, a subsequent re-deposition of the by-product of the etchingprocess onto the workpiece by the turbulent gases generated duringventing is mitigated.

It will be appreciated that the disclosed ion beam etching apparatus andassociated process that is described herein may comprise any type of dryetching apparatus, and in various embodiments may be configured toperform reactive ion beam etching, sputter etching/ion milling, plasmaetching, barrel etching, or the like.

Accordingly, in some embodiments, the present disclosure relates to anion beam etching apparatus that has a by-product redistributorconfigured to move a by-product from an etching process to directlybelow one or more baffles, so as to reduce re-deposition of an etchingby-product onto a workpiece.

In some embodiments, the present disclosure relates to an ion beametching apparatus. The etching apparatus includes a substrate holderdisposed within a processing chamber; a plasma source in communicationwith the processing chamber; a vacuum pump coupled to the processingchamber by way of an inlet; one or more baffles arranged between thesubstrate holder and a lower surface of the processing chamber; and aby-product redistributor configured to move a by-product from an etchingprocess from outside of the one or more baffles to directly below theone or more baffles. In some embodiments, the one or more bafflesinclude sidewalls that are separated by a space that is directly belowthe substrate holder. In some embodiments, the one or more baffles arecoupled to a sidewall of the processing chamber. In some embodiments,the one or more baffles include a first lower surface and a second lowersurface that is between the first lower surface and the lower surface ofthe processing chamber, the second lower surface arranged along anoutermost edge of the one or more baffles. In some embodiments, theby-product redistributor includes a heater arranged outside of the oneor more baffles; and a cooler arranged directly below the one or morebaffles, the heater and the cooler configured to generate a temperaturegradient along the bottom of the chamber that decreases in a directionfrom directly below the one or more baffles to the outside of the one ormore baffles 120. In some embodiments, the temperature gradient isgreater than or equal to approximately 10° C. In some embodiments, theheater and the cooler are arranged below the lower surface of theprocessing chamber. In some embodiments, the by-product redistributorincludes one or more additional vacuum pumps coupled to the processingchamber by way of one or more additional inlets that are arrangeddirectly below the one or more baffles, the one or more additionalvacuum pumps configured to generate a pressure gradient along the bottomof the chamber that decreases in a direction from directly below the oneor more baffles to the outside of the one or more baffles 120. In someembodiments, the one or more baffles include a baffle that continuouslyextends around a perimeter of the processing chamber.

In other embodiments, the present disclosure relates to an etchingapparatus. The etching apparatus includes a substrate holder disposedwithin a processing chamber and having a workpiece reception areaconfigured to hold a workpiece; a vacuum pump coupled to the processingchamber by way of an inlet; one or more baffles extending outward from asidewall of the processing chamber at vertical positions between thesubstrate holder and a lower surface of the processing chamber; and aby-product redistributor configured to move a by-product from an etchingprocess to directly below the one or more baffles. In some embodiments,the etching apparatus further includes a plasma source configured togenerate a plasma; and a grid system configured to accelerate ions fromthe plasma towards the substrate holder as an ion beam. In someembodiments, the by-product redistributor includes a cooler arrangeddirectly below the one or more baffles, the cooler configured togenerate a temperature gradient along the bottom of the chamber thatdecreases in a direction from directly below the one or more baffles tothe outside of the one or more baffles 120. In some embodiments, theby-product redistributor further includes a heater arranged outside ofthe one or more baffles. In some embodiments, the by-productredistributor includes one or more additional vacuum pumps coupled tothe processing chamber by way of one or more additional inlets that arearranged directly below the one or more baffles, the one or moreadditional vacuum pumps configured to generate a pressure gradient alongthe bottom of the chamber that decreases in a direction from directlybelow the one or more baffles to the outside of the one or more baffles120. In some embodiments, the one or more baffles include a first lowersurface and a second lower surface that is between the first lowersurface and the lower surface of the processing chamber; and the secondlower surface is arranged along an outermost edge of the one or morebaffles. In some embodiments, the one or more baffles include a singlebaffle coupled to the sidewall of the processing chamber and extendingcontinuously around a perimeter of the processing chamber as an unbrokenring.

In yet other embodiments, the present disclosure relates to a method ofperforming an etching process. The method includes generating a plasmawithin a plasma chamber in communication with a processing chamber;accelerating ions from the plasma toward a workpiece within theprocessing chamber to generate an ion beam, the ion beam performs anetching process that etches a material on the workpiece; and moving aby-product from the etching process to directly below one or morebaffles within the processing chamber. In some embodiments, moving theby-product from the etching process to below the one or more bafflesincludes generating a temperature gradient within the processing chamberdecreasing in a direction from directly below the one or more baffles ata first temperature to the outside of the one or more baffles at ahigher second temperature. In some embodiments, moving the by-productfrom the etching process to below the one or more baffles includesgenerating a pressure gradient within the processing chamber decreasingin a direction from directly below the one or more baffles at a firstpressure to the outside of the one or more baffles at a higher secondpressure. In some embodiments, the method further includes introducing agas into the plasma chamber, the plasma is generated from the gas withinthe plasma chamber; and venting the processing chamber upon completionof the etching process and after moving the by-product from the etchingprocess to directly below the one or more baffles.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. An etching apparatus, comprising: a substrate holder disposed within a processing chamber and comprising a workpiece reception surface configured to hold a workpiece, wherein a lower surface of the processing chamber has a first region that is directly below the workpiece reception surface and that is configured to receive a byproduct from an etching process; a baffle extending outward from a sidewall of the processing chamber at a vertical position between the substrate holder and the lower surface of the processing chamber, wherein the baffle covers a second region of the lower surface; and a byproduct redistributor configured to move the byproduct from the first region of the lower surface to the second region of the lower surface that is directly below the baffle.
 2. The etching apparatus of claim 1, a second baffle extending outward from a second sidewall of the processing chamber at a second vertical position between the substrate holder and the lower surface of the processing chamber, wherein an outermost sidewall of the baffle is separated from an outermost sidewall of the second baffle by a space that is directly over a center of the lower surface and directly below the substrate holder.
 3. The etching apparatus of claim 1, wherein an uppermost surface of the baffle is a surface that continuously and unbrokenly extends between outermost sidewalls of the baffle.
 4. The etching apparatus of claim 1, wherein the baffle has a first sidewall contacting the sidewall of the processing chamber and a second sidewall facing a center of the processing chamber, the second sidewall having a greater height than the first sidewall.
 5. The etching apparatus of claim 1, wherein the baffle is asymmetric about a vertical line bisecting the baffle.
 6. The etching apparatus of claim 1, wherein the byproduct from the etching process that is configured to be moved by the byproduct redistributor is on the lower surface.
 7. The etching apparatus of claim 1, further comprising: a heater arranged below the first region of the lower surface of the processing chamber; and a cooler arranged below the second region of the lower surface of the processing chamber.
 8. The etching apparatus of claim 7, wherein the baffle is directly between the cooler and the substrate holder.
 9. The etching apparatus of claim 7, wherein the baffle is directly above the cooler and the substrate holder is directly above the baffle.
 10. The etching apparatus of claim 7, wherein the heater is at least partially laterally outside of the substrate holder.
 11. An etching apparatus, comprising: a substrate holder disposed within a processing chamber and comprising a workpiece reception surface that is configured to hold a workpiece and that faces a lower surface of the processing chamber, wherein the lower surface of the processing chamber has a first region that is directly below the workpiece reception surface and that is configured to receive a byproduct from an etching process; a baffle extending outward from a sidewall of the processing chamber at a vertical position between the substrate holder and the lower surface of the processing chamber, wherein the baffle is separated from the lower surface of the processing chamber by an opening that faces the first region of the lower surface; and a byproduct redistributor configured to move the byproduct from the first region of the lower surface to directly below the baffle via the opening.
 12. The etching apparatus of claim 11, wherein the baffle comprises an upper surface that continuously extends between outermost sidewalls of the baffle as viewed along a cross-section of the baffle, the upper surface intersecting the sidewall of the processing chamber.
 13. The etching apparatus of claim 11, wherein the baffle is separated from the lower surface of the processing chamber by a space, the space laterally between the baffle and a center of the lower surface.
 14. The etching apparatus of claim 11, wherein the byproduct redistributor is configured to move the byproduct laterally along the lower surface from directly below the substrate holder to directly below the baffle.
 15. The etching apparatus of claim 11, further comprising: a heater arranged directly below the first region of the lower surface of the processing chamber; and a cooler arranged directly below the baffle.
 16. An etching apparatus, comprising: a substrate holder disposed within a processing chamber, wherein a lower surface of the processing chamber has a first region that is directly below the substrate holder and that is configured to receive a byproduct from an etching process; a baffle extending outward from a sidewall of the processing chamber at a vertical position between the substrate holder and the lower surface of the processing chamber; and a byproduct redistributor configured to laterally move the byproduct from the etching process along the lower surface from the first region of the lower surface that is outside of the baffle to directly below the baffle.
 17. The etching apparatus of claim 16, wherein the baffle comprises a protrusion extending outward from a lower surface of the baffle that faces a bottom of the processing chamber, the protrusion extending to a bottommost surface of the baffle that is separated from the lower surface of the processing chamber by a non-zero distance.
 18. The etching apparatus of claim 16, wherein the byproduct redistributor is configured to move the byproduct from the etching process that has landed on the lower surface.
 19. The etching apparatus of claim 16, wherein the lower surface continuously extends between a first outlet arranged within the lower surface and a second outlet arranged within the lower surface.
 20. The etching apparatus of claim 19, wherein the baffle continuously extends from directly over the first outlet to directly over the second outlet. 